[ULPIANUS libro trigesimo ad Sabinum. ] §17.2.31.prUt sit pro socio actio, societatem intercedere oportet: nec enim sufficit rem esse communem, nisi societas intercedit.
[ULPIANUS in his thirtieth book on Sabinus] In order for there to be an action on partnership, it is necessary that a partnership exist; for it is not sufficient that a thing is held in common, unless a partnership exists.
communiter autem res agi potest etiam citra societatem, ut puta cum non affectione societatis incidimus in communionem, ut euenit in re duobus legata, item si a duobus simul empta res sit, aut si hereditas uel donatio communiter nobis obuenit, aut si a duobus separatim emimus partes eorum non socii futuri.
However, business can be conducted in common even without a partnership, for instance, when we enter into a state of common ownership not through the intention of partnership, as happens in the case of a thing bequeathed to two persons, likewise if a thing is bought by two persons at the same time, or if an inheritance or a gift falls to us in common, or if we buy their shares separately from two persons, not intending to become partners.